A conventional automatically opening and closing umbrella, such as taught by U.S. Pat. No. 4,421,133 by Yueh Huang, U.S. Pat. No. 4,535,374 and 4,823,821 by San-Tong Day and U.S. Pat. No. 4,825,888 by Tseng Su, disclosed a short spring for opening the umbrella which is retained within an intermediate tubular shaft between an upper tubular shaft and a lower tubular shaft. Since the spring for opening the umbrella is so short between the upper and lower shafts, the spring must be made of larger or coarse steel wire to develop enough elastic force so that it requires a big force for depressing the umbrella grip for restoring the elastic force of the spring after being released, easily causing tiredness of an umbrella user or possibly causing loss of a user's interest.
Meanwhile, it is easy to falsely operate the conventional automatic umbrella, for instance, in depressing the push button 6 of Day's U.S. Pat. No. 4,823,821, a suddenly continuous depression of the button 6 or uncareful push button operation, the umbrella frame and cloth may be first opened and then closed quickly. A false operation may be done for such conventional automatic umbrella.
Furthermore, the conventional automatic opening and closing umbrella has a complex structure or mechanism, thereby increasing its production cost and maintenance problems.
The present inventor has found the drawbacks of the conventional automatic opening and closing umbrellas and invented the present simply-constructed umbrella for preventing false operation.